LTE is the 4th generation (4G) wireless data communication standard that supersedes WCDMA and other 3rd generation (3G) ones. Unfortunately, the far more diverse range of frequencies that the carriers around the world uses for this standard is a big headache, especially for Apple.

This is because a single model of iPhone tries to support as much of the entire world as possible in order to simplify the lineup. iPhone 4S, the last model before LTE support, indeed came in a single model for the entire world. In contrast, iPhone 5 and 5S had to be split up into multiple models that each had differing LTE band support. This was largely because the chipset couldn't support all the needed bands at once.

This meant that an iPhone bought in one country may not support LTE in another country. With iPhone 5, you needed model A1429 (for Sprint and Verizon in US) if you wanted it to use LTE in Korea. A1428 (for AT&T and T-Mobile in US) wouldn't do. That may have been a factor in the Korean carriers not automatically enabling LTE for foreign phones until 2014.

Situation is similar with iPhone 6S and 6S Plus, which adds a few more obscure or upcoming LTE bands on an already extensive array of support. There are still three specific models for each type, but one is for adding an upcoming AT&T-specific band 30 (A1633, A1634) and the other is for Chinese release (A1700, A1699). They are identical to the general model (A1688, A1687) otherwise.

However, not everything is in the clear. VoLTE (LTE-based voice calls) support is still not a universally supported feature among phones and carriers are still enabling this on a manual basis as of this writing. Owners of internationally bought iPhone 6, 6 Plus, 6S, and 6S Plus still need a visit to the carrier branch or store.

I had two iPhone 6S Plus that came from overseas - one is a "SIM-Free" version from Japan that you saw in my earlier post and the other is from United States intended for T-Mobile network. Both are model A1687 and the same version expected to be sold in Korea in a few days' time (October 23, 2015). The former was registered at an SK Telecom branch office as "OMD Apple VoLTE", the same title my iPhone 6 Plus received last year. The latter was registered at a local certified SK Telecom store as "OMD Apple VoLTE_6S" as shown here. Only after doing this, and waiting for a while to let the network know of the change, did the VoLTE function start to work.

The interesting (or cumbersome) part of doing the registration at a certified store was that it required me to have a separate, pre-registered device that was not in use to help with the registration. According to the store, once I inserted the SIM card into my iPhone 6S Plus, the network automatically registered it under "OMD Default Handset" because it wasn't recognized. In order to change that, the SIM card had to be put into another device so as to make the 6S Plus not be associated with any SIM card. Only then could the re-registration could proceed. Branch offices didn't have this requirement, so I have to assume that the system provided to the store is limited compared to the branch.

As many people including myself noticed, iOS 9 beta 1 and watchOS 2 beta 1 had horrible battery life. After two weeks of bearing this, beta 2 of both OSes arrived on June 23 (June 24 in Korea), amidst the hope that they would fix or lessen this battery problem. The one for Apple Watch was pulled just after release, but then re-uploaded a few hours later. I was able to have these betas installed on my iPhone 6 Plus and my Apple Watch as soon as I could.

It's now been more than two full days since and Apple Watch has finally been launched in Korea with people lining up in front of the store despite the rain. For those people who were now wondering if the new beta is anything worth diving into for their shiny new watch, here's my verdict. Yes, it's better than 2.0 beta 1, but no, it's not quite as battery-efficient as 1.0.1. As for the iOS 9 beta 2, its battery life is back to being as good as 8.3 for my iPhone 6 Plus, which was excellent.

This is good news for iPhones, but for Apple Watch, sticking to a non-beta version is still recommended if you value long battery life. As you've seen before, 1.0 / 1.0.1 version delivered about 26 hours of continuous usage on average for me, which included daily exercising and moderate interactions. 2.0 beta 1 effectively halved this, often getting only 12 hours and conservative use barely pushing it to 18 hours. So I'd say that's roughly 15 hours per charge, to be generous. With 2.0 beta 2, I've been getting about 21 hours of use daily so far, barely good enough for one-charge-a-day routine but lacking any comfortable margin.

Meanwhile, the apps do run smoother again, almost like 1.0.1, making the experience less annoying overall. There are still some noticeable bugs, like the one that prevents scrolling with digital crown in certain notifications. This has been persisting since beta 1. Another problem I am seeing is that the voice call volume is quite low and rebooting doesn't fix it. This one seems to be new for this beta. Anyone who's seeking cutting edge, beware.

As it's about a week away from Apple Watch's official launch in Korea (and other 2nd wave countries), I wanted to provide an update on the current state of my watch. This is to hint at its durability and upcoming functions.

On the durability side, things are more or less as expected. As I went traveling in New Zealand, the watch accidentally brushed with the walls of the buildings a few times while walking around. It left two slight scratches, one on the aluminum frame and one the glass. The latter is nearly invisible unless seen at a right angle under a bright light. Sapphire glass would've fared even better, but the ion-hardened one on this Sport version seems to be alright, too, given that's all it's gotten after kisses with rough surface.

Area on the band with lots of rubbings appear bright under the light

As for the band, the front side had no visible changes. The back side had been showing marks where rubbings happened only a few days after wearing, but they had no effect on the functional and performance aspects of the band. So unless you take the watch off your wrist to see the marks, you won't be able to tell the difference from day 1 to day 45 use.

Considering all this, I think Apple Watch Sport should be quite usable for a long time, under normal circumstances. Meanwhile, I also had the chance to explore the upcoming OS, watchOS 2, as WWDC 2015 event unfolded nearly two weeks ago.

On the Memorial Day in Korea earlier this month, the night sky was clear and had three planets shining brightly in the sky at the same time. I took my astrophotography equipment outside and got some burst mode photos of the planets.

It seemed that Venus was quite bright and the default camera app didn't have enough adjustments available to make it dark enough to reveal any details on the half-disc. Also, Jupiter now being in the lower altitude hampered the details somewhat. Other than that, things turned out fine. It was nice to have a direct comparison of the apparent sizes between the planets.